Wide ratio transmissions having three gear sets and a stationary planetary member

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least eight forward speed ratios and one reverse speed ratio. The transmission family members include three planetary gear sets having seven torque-transmitting mechanisms and three fixed interconnections. The powertrain includes an engine and torque converter that is continuously connected to at least one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The seven torque-transmitting mechanisms provide interconnections between various gear members and with the transmission housing, and are operated in combinations of two to establish at least eight forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a family of power transmissions havingthree planetary gear sets that are controlled by seventorque-transmitting devices to provide at least eight forward speedratios and at least one reverse speed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times. The number of forward speed ratios that are availablein the transmission determines the number of times the engine torquerange is repeated. Early automatic transmissions had two speed ranges.This severely limited the overall speed range of the vehicle andtherefore required a relatively large engine that could produce a widespeed and torque range. This resulted in the engine operating at aspecific fuel consumption point during cruising, other than the mostefficient point. Therefore, manually-shifted (countershafttransmissions) were the most popular.

With the advent of three- and four-speed automatic transmissions, theautomatic shifting (planetary gear) transmission increased in popularitywith the motoring public. These transmissions improved the operatingperformance and fuel economy of the vehicle. The increased number ofspeed ratios reduces the step size between ratios and therefore improvesthe shift quality of the transmission by making the ratio interchangessubstantially imperceptible to the operator under normal vehicleacceleration.

It has been suggested that the number of forward speed ratios beincreased to six or more. Six-speed transmissions are disclosed in U.S.Pat. No. 4,070,927 issued to Polak on Jan. 31, 1978; and U.S. Pat. No.6,422,969 issued to Raghavan and Usoro on Jul. 23, 2002.

Six-speed transmissions offer several advantages over four- andfive-speed transmissions, including improved vehicle acceleration andimproved fuel economy. While many trucks employ power transmissionshaving six or more forward speed ratios, passenger cars are stillmanufactured with three- and four-speed automatic transmissions andrelatively few five or six-speed devices due to the size and complexityof these transmissions.

Seven-speed transmissions are disclosed in U.S. Pat. No. 6,623,397issued to Raghavan, Bucknor and Usoro. Eight speed transmissions aredisclosed in U.S. Pat. No. 6,425,841 issued to Haka. The Hakatransmission utilizes three planetary gear sets and six torquetransmitting devices, including two brakes and two clutches, to provideeight forward speed ratios and a reverse speed ratio. One of theplanetary gear sets is positioned and operated to establish two fixedspeed input members for the remaining two planetary gear sets. The Hakatransmission requires two double-transition shifts. Seven-, eight- andnine-speed transmissions provide further improvements in accelerationand fuel economy over six-speed transmissions. However, like thesix-speed transmissions discussed above, the development of seven-,eight-and nine-speed transmissions has been precluded because ofcomplexity, size and cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved familyof transmissions having three planetary gear sets controlled to provideat least eight forward speed ratios and at least one reverse speedratio.

In one aspect of the present invention, the family of transmissions hasthree planetary gear sets, each of which includes a first, second andthird member, which members may comprise a sun gear, a ring gear, or aplanet carrier assembly member.

In referring to the first, second and third gear sets in thisdescription and in the claims, these sets may be counted “first” to“third” in any order in the drawings (i.e., left to right, right toleft, etc.). Additionally, the first, second or third members of eachgear set may be counted “first” to “third” in any order in the drawings(i.e., top to bottom, bottom to top, etc.) for each gear set.

In another aspect of the present invention, planet carrier assemblymembers of each of the planetary gear sets may be single pinion-carriersor double pinion-carriers.

In yet another aspect of the present invention, a first member of thefirst planetary gear set is continuously interconnected with a firstmember of the second planetary gear set through a first interconnectingmember.

In yet another aspect of the present invention, a second member of thesecond planetary gear set is continuously interconnected with a firstmember of the third planetary gear set through a second interconnectingmember.

In yet another aspect of the present invention, a third member of thesecond planetary gear set is continuously interconnected with astationary member through a third interconnecting member.

In yet a further aspect of the invention, each family memberincorporates an input shaft which is continuously connected with amember of the planetary gear sets and an output shaft which iscontinuously connected with another member of the planetary gear sets.The third member of the second planetary gear set continuouslyinterconnected with the stationary member is different from the membersinterconnected with the input shaft and the output shaft, respectively.

In still a further aspect of the invention, a first torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst planetary gear set with a member of the second or third planetarygear set.

In another aspect of the invention, a second torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with a member of the first or second planetarygear set.

In a still further aspect of the invention, a third torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst planetary gear set with another member of the first, second orthird planetary gear set.

In a still further aspect of the invention, a fourth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with another member of the first, second orthird planetary gear set.

In a still further aspect of the invention, a fifth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst or third planetary gear set with a member of the second planetarygear set. Alternatively, a fifth torque-transmitting mechanism, such asa brake, selectively interconnects a member of the first or thirdplanetary gear set with a stationary member (transmission housing).

In still another aspect of the invention, a sixth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thesecond or third planetary gear set with another member of the first,second or third planetary gear set. Alternatively, a sixthtorque-transmitting mechanism, such as a brake, selectivelyinterconnects a member of the second or third planetary gear set withthe stationary member (transmission housing).

In still another aspect of the invention, a seventh torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst, second or third planetary gear set with another member of thefirst, second or third planetary gear set. Alternatively, the seventhtorque-transmitting mechanism, such as a brake, selectivelyinterconnects a member of the first, second or third planetary gear setwith the stationary member (transmission housing).

In still another aspect of the invention, the seven torque-transmittingmechanisms are selectively engageable in combinations of two to yield atleast eight forward speed ratios and at least one reverse speed ratio.

The resulting transmission provides a significantly wider ratio spreadin comparison to transmissions with fewer speed ratios.

The above features and other features and advantages of the presentinvention are readily apparent from the following detailed descriptionof the best modes for carrying out the invention when taken inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

FIG. 1 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1 a;

FIG. 2 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 2 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2 a;

FIG. 3 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 3 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3 a;

FIG. 4 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 4 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4 a;

FIG. 5 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 5 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5 a;

FIG. 6 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 6 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6 a;

FIG. 7 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 7 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7 a;

FIG. 8 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 8 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8 a;

FIG. 9 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 9 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9 a;

FIG. 10 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 10 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 10 a;

FIG. 11 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 11 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 11 a;

FIG. 12 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 12 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 12 a;

FIG. 13 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 13 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 13 a;

FIG. 14 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 14 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 14 a;

FIG. 15 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 15 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 15 a;

FIG. 16 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

FIG. 16 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 16 a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, there is shown in FIG.1 a a powertrain 10 having a conventional engine and torque converter12, a planetary transmission 14, and a conventional final drivemechanism 16.

The planetary transmission 14 includes an input shaft 17 continuouslyconnected with the engine and torque converter 12, a planetary geararrangement 18, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 18 includesthree planetary gear sets 20, 30 and 40.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly member 26. The planet carrierassembly member 26 includes a plurality of pinion gears 27 rotatablymounted on a carrier member 29 and disposed in meshing relationship withboth the sun gear member 22 and the ring gear member 24.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 rotatablymounted on a carrier member 49 and disposed in meshing relationship withboth the sun gear member 42 and the ring gear member 44.

The planetary gear arrangement also includes seven torque-transmittingmechanisms 50, 52, 54, 56, 57, 58 and 59. The torque-transmittingmechanisms 50, 52, 54 and 56 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque-transmitting mechanisms57, 58 and 59 are stationary-type torque-transmitting mechanisms,commonly termed brakes or reaction clutches.

The input shaft 17 is continuously connected with the sun gear member42, and the output shaft 19 is continuously connected with the ring gearmember 24. The sun gear member 22 is continuously connected with thering gear member 34 through the interconnecting member 70. Theinterconnecting member 70 may be one component or separate components.The planet carrier assembly member 36 is continuously connected with thering gear member 44 through the interconnecting member 72. The sun gearmember 32 is continuously connected with the transmission housing 60through the interconnecting member 74.

The sun gear member 22 is selectively connectable with the planetcarrier assembly member 46 through the clutch 50. The planet carrierassembly member 26 is selectively connectable with the planet carrierassembly member 46 through the clutch 52. The planet carrier assemblymember 26 is selectively connectable with the sun gear member 42 throughthe clutch 54. The ring gear member 24 is selectively connectable withthe planet carrier assembly member 26 through the clutch 56. The ringgear member 34 is selectively connectable with the transmission housing60 through the brake 57. The planet carrier assembly member 26 isselectively connectable with the transmission housing 60 through thebrake 58. The planet carrier assembly member 46 is selectivelyconnectable with the transmission housing 60 through the brake 59.

As shown in FIG. 1 b, and in particular the truth table disclosedtherein, the torque-transmitting mechanisms are selectively engaged incombinations of two to provide eight forward speed ratios and tworeverse speed ratios.

The second reverse (Reverse 2) speed ratio is established with theengagement of the clutch 50 and the brake 58. The clutch 50 connects thesun gear member 22 with the planet carrier assembly member 46, and thebrake 58 connects the planet carrier assembly member 26 with thetransmission housing 60. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 46 andthe sun gear member 22 rotate at the same speed as the ring gear member34. The ring gear member 44 rotates at the same speed as the planetcarrier assembly member 36. The ring gear member 44 rotates at a speeddetermined from the speed of the planet carrier assembly member 46, thespeed of the sun gear member 42 and the ring gear/sun gear tooth ratioof the planetary gear set 40. The sun gear member 32 does not rotate.The ring gear member 34 rotates at a speed determined from the speed ofthe planet carrier assembly member 36 and the ring gear/sun gear toothratio of the planetary gear set 30. The planet carrier assembly member26 does not rotate. The ring gear member 24 rotates at the same speed asthe output shaft 19. The ring gear member 24, and therefore the outputshaft 19, rotates at a speed determined from the speed of the sun gearmember 22 and the ring gear/sun gear tooth ratio of the planetary gearset 20. The numerical value of the second reverse (Reverse 2) speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30 and 40.

The first reverse (Reverse 1) speed ratio is established with theengagement of the clutch 56 and the brake 59. The clutch 56 connects thering gear member 24 with the planet carrier assembly member 26, and thebrake 59 connects the planet carrier assembly member 46 with thetransmission housing 60. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 46 doesnot rotate. The ring gear member 44 rotates at the same speed as theplanet carrier assembly member 36. The ring gear member 44 rotates at aspeed determined from the speed of the sun gear member 42 and the ringgear/sun gear tooth ratio of the planetary gear set 40. The sun gearmember 32 does not rotate. The ring gear member 34 and the planetarygear set 20 rotate at the same speed as the output shaft 19. The ringgear member 34 rotates at a speed determined from the speed of theplanet carrier assembly member 36 and the ring gear/sun gear tooth ratioof the planetary gear set 30. The numerical value of the first reverse(Reverse 1) speed ratio is determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 30 and 40.

The first forward speed ratio is established with the engagement of theclutch 52 and the brake 58. The clutch 52 connects the planet carrierassembly member 26 with the planet carrier assembly member 46, and thebrake 58 connects the planet carrier assembly member 26 with thetransmission housing 60. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 46 andthe planet carrier assembly member 26 do not rotate. The ring gearmember 44 rotates at the same speed as the planet carrier assemblymember 36. The ring gear member 44 rotates at a speed determined fromthe speed of the sun gear member 42 and the ring gear/sun gear toothratio of the planetary gear set 40. The sun gear member 32 does notrotate. The ring gear member 34 rotates at the same speed as the sungear member 22. The ring gear member 34 rotates at a speed determinedfrom the speed of the planet carrier assembly member 36 and the ringgear/sun gear tooth ratio of the planetary gear set 30. The ring gearmember 24 rotates at the same speed as the output shaft 19. The ringgear member 24, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20, 30 and 40.

The second forward speed ratio is established with the engagement of theclutch 52 and the brake 57. The clutch 52 connects the planet carrierassembly member 26 with the planet carrier assembly member 46, and thebrake 57 connects the ring gear member 34 with the transmission housing60. The sun gear member 42 rotates at the same speed as the input shaft17. The planet carrier assembly member 26 rotates at the same speed asthe planet carrier assembly member 46. The ring gear member 44, theplanetary gear set 30 and the sun gear member 22 do not rotate. Theplanet carrier assembly member 46 rotates at a speed determined from thespeed of the sun gear member 42 and the ring gear/sun gear tooth ratioof the planetary gear set 40. The ring gear member 24 rotates at thesame speed as the output shaft 19. The ring gear member 24, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the planet carrier assembly member 26 and the ring gear/sungear tooth ratio of the planetary gear set 20. The numerical value ofthe second forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 20 and 40.

The third forward speed ratio is established with the engagement of theclutches 50 and 52. The clutch 50 connects the sun gear member 22 withthe planet carrier assembly member 46, and the clutch 52 connects theplanet carrier assembly member 26 with the planet carrier assemblymember 46. The sun gear member 42 rotates at the same speed as the inputshaft 17. The planet carrier assembly member 46, the ring gear member 34and the planetary gear set 20 rotate at the same speed as the outputshaft 19. The ring gear member 44 rotates at the same speed as theplanet carrier assembly member 36. The ring gear member 44 rotates at aspeed determined from the speed of the planet carrier assembly member46, the speed of the sun gear member 42 and the ring gear/sun gear toothratio of the planetary gear set 40. The sun gear member 32 does notrotate. The ring gear member 34, and therefore the output shaft 19,rotates at a speed determined from the speed of the planet carrierassembly member 36 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The numerical value of the third forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 30 and 40.

The fourth forward speed ratio is established with the engagement of theclutches 52 and 54. The clutch 52 connects the planet carrier assemblymember 26 with the planet carrier assembly member 46 and the clutch 54connects the planet carrier assembly member 26 with the sun gear member42. The planetary gear set 40 and the planet carrier assembly members 26and 36 rotate at the same speed as the input shaft 17. The sun gearmember 32 does not rotate. The ring gear member 34 rotates at the samespeed as the sun gear member 22. The ring gear member 34 rotates at aspeed determined from the speed of the planet carrier assembly member 36and the ring gear/sun gear tooth ratio of the planetary gear set 30. Thering gear member 24 rotates at the same speed as the output shaft 19.The ring gear member 24, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member26, the speed of the sun gear member 22 and the ring gear/sun gear toothratio of the planetary gear set 20. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 20 and 30.

The fifth forward speed ratio is established with the engagement of theclutches 54 and 56. In this configuration, the input shaft 17 isdirectly connected with the output shaft 19. The numerical value of thefifth forward speed ratio is 1.

The sixth forward speed ratio is established with the engagement of theclutches 50 and 54. The clutch 50 connects the sun gear member 22 withthe planet carrier assembly member 46, and the clutch 54 connects theplanet carrier assembly member 26 with the sun gear member 42. The sungear member 42 and the planet carrier assembly member 26 rotate at thesame speed as the input shaft 17. The planet carrier assembly member 46and the sun gear member 22 rotate at the same speed as the ring gearmember 34. The ring gear member 44 rotates at the same speed as theplanet carrier assembly member 36. The ring gear member 44 rotates at aspeed determined from the speed of the planet carrier assembly member46, the speed of the sun gear member 42 and the ring gear/sun gear toothratio of the planetary gear set 40. The sun gear member 32 does notrotate. The ring gear member 34 rotates at a speed determined from thespeed of the planet carrier assembly member 36 and the ring gear/sungear tooth ratio of the planetary gear set 30. The ring gear member 24rotates at the same speed as the output shaft 19. The ring gear member24, and therefore the output shaft 19, rotates at a speed determinedfrom the speed of the planet carrier assembly member 26, the speed ofthe sun gear member 22 and the ring gear/sun gear tooth ratio of theplanetary gear set 20. The numerical value of the sixth forward speedratio is determined utilizing ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30 and 40.

The seventh forward speed ratio is established with the engagement ofthe clutch 54 and the brake 57. The clutch 54 connects the planetcarrier assembly member 26 with the sun gear member 42, and the brake 57connects the ring gear member 34 with the transmission housing 60. Thesun gear member 42 and the planet carrier assembly member 26 rotate atthe same speed as the input shaft 17. The ring gear member 44, theplanetary gear set 30 and the sun gear member 22 do not rotate. The ringgear member 24 rotates at the same speed as the output shaft 19. Thering gear member 24, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member 26and the ring gear/sun gear tooth ratio of the planetary gear set 20. Thenumerical value of the seventh forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set20.

The eighth forward speed ratio is established with the engagement of theclutch 54 and the brake 59. The clutch 54 connects the planet carrierassembly member 26 with the sun gear member 42, and the brake 59connects the planet carrier assembly member 46 with the transmissionhousing 60. The sun gear member 42 and the planet carrier assemblymember 26 rotate at the same speed as the input shaft 17. The planetcarrier assembly member 46 does not rotate. The ring gear member 44rotates at the same speed as the planet carrier assembly member 36. Thering gear member 44 rotates at a speed determined from the speed of thesun gear member 42 and the ring gear/sun gear tooth ratio of theplanetary gear set 40. The sun gear member 32 does not rotate. The ringgear member 34 rotates at the same speed as the sun gear member 22. Thering gear member 34 rotates at a speed determined from the speed of theplanet carrier assembly member 36 and the ring gear/sun gear tooth ratioof the planetary gear set 30. The ring gear member 24 rotates at thesame speed as the output shaft 19. The ring gear member 24, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the planet carrier assembly member 26, the speed of the sungear member 22 and the ring gear/sun gear tooth ratio of the planetarygear set 20. The numerical value of the eight forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30 and 40.

As set forth above, the engagement schedule for the torque-transmittingmechanisms is shown in the truth table of FIG. 1 b. This truth tablealso provides an example of speed ratios that are available utilizingthe ring gear/sun gear tooth ratios given by way of example in FIG. 1 b.The N_(R1)/S_(R1) value is the tooth ratio of the planetary gear set 20;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set 30;and the N_(R3)/S_(R3) value is the tooth ratio of the planetary gear set40. Also, the chart of FIG. 1 b describes the ratio steps that areattained utilizing the sample of tooth ratios given. For example, thestep ratio between the first and second forward speed ratios is 1.74,while the step ratio between the second reverse speed ratio (Reverse 2)and first forward ratio is −0.87. It should be noted that the singlestep forward ratio changes are of the single transition variety.

FIG. 2 a shows a powertrain 110 having a conventional engine and torqueconverter 12, a planetary transmission 114, and a conventional finaldrive mechanism 16.

The planetary transmission 114 includes an input shaft 17 continuouslyconnected with the engine and torque converter 12, a planetary geararrangement 118, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 118 includesthree planetary gear sets 120, 130 and 140.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly member 126. The planet carrierassembly member 126 includes a plurality of pinion gears 127 rotatablymounted on a carrier member 129 and disposed in meshing relationshipwith both the sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of pinion gears 137 rotatablymounted on a carrier member 139 and disposed in meshing relationshipwith both the sun gear member 132 and the ring gear member 134.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 rotatablymounted on a carrier member 149 and disposed in meshing relationshipwith both the sun gear member 142 and the ring gear member 144.

The planetary gear arrangement 118 also includes seventorque-transmitting mechanisms 150, 152, 154, 156, 157, 158 and 159. Thetorque-transmitting mechanisms 150, 152, 154 and 156 are rotating-typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 157, 158 and 159 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the sun gear member142, and the output shaft 19 is continuously connected with the ringgear member 124. The sun gear member 122 is continuously connected withthe planet carrier assembly member 136 through the interconnectingmember 170. The interconnecting member 170 may be one component orseparate components. The ring gear member 134 is continuously connectedwith the planet carrier assembly member 146 through the interconnectingmember 172. The sun gear member 132 is continuously connected with thetransmission housing 160 through the interconnecting member 174.

The planet carrier assembly member 126 is selectively connectable withthe planet carrier assembly member 136 through the clutch 150. Theplanet carrier assembly member 136 is selectively connectable with thering gear member 144 through the clutch 152. The planet carrier assemblymember 126 is selectively connectable with the sun gear member 142through the clutch 154. The sun gear member 142 is selectivelyconnectable with the planet carrier assembly member 146 through theclutch 156. The planet carrier assembly member 126 is selectivelyconnectable with the transmission housing 160 through the brake 157. Thering gear member 144 is selectively connectable with the transmissionhousing 160 through the brake 158. The planet carrier assembly member136 is selectively connectable with the transmission housing 160 throughthe brake 159.

The truth table of FIG. 2 b describes the engagement sequence utilizedto provide eight forward speed ratios and three reverse speed ratios inthe planetary gear arrangement 118 shown in FIG. 2 a.

The truth tables given in FIGS. 2 b, 3 b, 4 b, 5 b, 6 b, 7 b, 8 b, 9 b,10 b, 11 b, 12 b, 13 b, 14 b, 15 b and 16 b show the engagementsequences for the torque-transmitting mechanisms to provide at leasteight forward speed ratios and at least one reverse ratio. As shown anddescribed above for the configuration in FIG. 1 a, those skilled in theart will understand from the respective truth tables how the speedratios are established through the planetary gear sets identified in thewritten description.

The truth table of FIG. 2 b also provides an example of the ratios thatcan be attained with the family members shown in FIG. 2 a utilizing thesample tooth ratios given in FIG. 2 b. The N_(R1)/S_(R1) value is thetooth ratio of the planetary gear set 120; the N_(R2)/S_(R2) value isthe tooth ratio of the planetary gear set 130; and the N_(R3)/S_(R3)value is the tooth ratio of the planetary gear set 140. Also shown inFIG. 2 b are the ratio steps between single step ratios in the forwarddirection as well as the second reverse (Reverse 2) to first ratio step.For example, the first to second step ratio is 1.81. It should also benoted that the single step and double step forward ratio interchangesare of the single transition variety.

Turning to FIG. 3 a, a powertrain 210 includes the engine and torqueconverter 12, a planetary transmission 214, and a final drive mechanism16. The planetary transmission 214 includes an input shaft 17continuously connected with the engine and torque converter 12, aplanetary gear arrangement 218, and an output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 218 includes three planetary gear sets 220, 230 and 240.

The planetary gear set 220 includes a sun gear member 222, a ring gearmember 224, and a planet carrier assembly member 226. The planet carrierassembly member 226 includes a plurality of pinion gears 227 rotatablymounted on a carrier member 229 and disposed in meshing relationshipwith both the sun gear member 222 and the ring gear member 224.

The planetary gear set 230 includes a sun gear member 232, a ring gearmember 234, and a planet carrier assembly member 236. The planet carrierassembly member 236 includes a plurality of pinion gears 237 rotatablymounted on a carrier member 239 and disposed in meshing relationshipwith both the sun gear member 232 and the ring gear member 234.

The planetary gear set 240 includes a sun gear member 242, a ring gearmember 244, and a planet carrier assembly member 246. The planet carrierassembly member 246 includes a plurality of pinion gears 247 rotatablymounted on a carrier member 249 and disposed in meshing relationshipwith both the sun gear member 242 and the ring gear member 244.

The planetary gear arrangement 218 also includes seventorque-transmitting mechanisms 250, 252, 254, 256, 257, 258 and 259. Thetorque-transmitting mechanisms 250, 252, 254 and 256 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 257, 258 and 259 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 246, and the output shaft 19 is continuously connectedwith the sun gear member 222. The ring gear member 224 is continuouslyconnected with the planet carrier assembly member 236 through theinterconnecting member 270. The sun gear member 232 is continuouslyconnected with the sun gear member 242 through the interconnectingmember 272. The ring gear member 234 is continuously connected with thetransmission housing 260 through the interconnecting member 274.

The planet carrier assembly member 226 is selectively connectable withthe transmission housing 260 through the brake 250. The ring gear member244 is selectively connectable with the transmission housing 260 throughthe brake 252. The ring gear member 224 is selectively connectable withthe transmission housing 260 through the brake 254. The ring gear member224 is selectively connectable with the planet carrier assembly member226 through the clutch 256. The planet carrier assembly member 236 isselectively connectable with the ring gear member 244 through the clutch257. The planet carrier assembly member 226 is selectively connectablewith the planet carrier assembly member 246 through the clutch 258. Thesun gear member 242 is selectively connectable with the planet carrierassembly member 246 through the clutch 259.

As shown in the truth table in FIG. 3 b, the torque-transmittingmechanisms are engaged in combinations of two to establish eight forwardspeed ratios and three reverse ratio.

The truth table of FIG. 3 b also provides an example of speed ratiosthat are available with the family member described above. Theseexamples of speed ratios are determined utilizing the tooth ratios givenin FIG. 3 b. The N_(R1)/S_(R1) value is the tooth ratio of the planetarygear set 220; the N_(R2)/S_(R2) value is the tooth ratio of theplanetary gear set 230; and the N_(R3)/S_(R3) value is the tooth ratioof the planetary gear set 240. Also depicted in FIG. 3 b is a chartrepresenting the ratio steps between adjacent forward speed ratios andthe reverse speed ratio. For example, the first to second ratiointerchange has a step of 1.85. It can also be readily determined fromthe truth table of FIG. 3 b that all of the single step and double stepforward ratio interchanges are of the single transition variety.

A powertrain 310, shown in FIG. 4 a, includes the engine and torqueconverter 12, a planetary transmission 314, and the final drivemechanism 16. The planetary transmission 314 includes an input shaft 17continuously connected with the engine and torque converter 12, aplanetary gear arrangement 318, and output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 318 includes three planetary gear sets 320, 330 and 340.

The planetary gear set 320 includes a sun gear member 322, a ring gearmember 324, and a planet carrier assembly member 326. The planet carrierassembly member 326 includes a plurality of pinion gears 327 rotatablymounted on a carrier member 329 and disposed in meshing relationshipwith both the sun gear member 322 and the ring gear member 324.

The planetary gear set 330 includes a sun gear member 332, a ring gearmember 334, and a planet carrier assembly member 336. The planet carrierassembly member 336 includes a plurality of pinion gears 337 rotatablymounted on a carrier member 339 and disposed in meshing relationshipwith both the sun gear member 332 and the ring gear member 334.

The planetary gear set 340 includes a sun gear member 342, a ring gearmember 344, and a planet carrier assembly member 346. The planet carrierassembly member 346 includes a plurality of pinion gears 347 rotatablymounted on a carrier member 349 and disposed in meshing relationshipwith both the sun gear member 342 and the ring gear member 344.

The planetary gear arrangement 318 also includes seventorque-transmitting mechanisms 350, 352, 354, 356, 357, 358 and 359. Thetorque-transmitting mechanisms 350, 352, 354 and 356 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 357, 358 and 359 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the ring gear member342, and the output shaft 19 is continuously connected with the sun gearmember 322. The ring gear member 324 is continuously connected with theplanet carrier assembly member 326 through the interconnecting member370. The ring gear member 334 is continuously connected with the planetcarrier assembly member 346 through the interconnecting member 372. Thesun gear member 332 is continuously connected with the transmissionhousing 360 through the interconnecting member 374.

The planet carrier assembly member 326 is selectively connectable withthe sun gear member 322 through the clutch 350. The planet carrierassembly member 336 is selectively connectable with the ring gear member344 through the clutch 352. The planet carrier assembly member 326 isselectively connectable with the sun gear member 342 through the clutch354. The sun gear member 342 is selectively connectable with the planetcarrier assembly member 346 through the clutch 356. The planet carrierassembly member 346 is selectively connectable with the transmissionhousing 360 through the brake 357. The planet carrier assembly member326 is selectively connectable with the transmission housing 360 throughthe brake 358. The ring gear member 344 is selectively connectable withthe transmission housing 360 through the brake 359.

The truth table shown in FIG. 4 b describes the engagement combinationand the engagement sequence necessary to provide three reverse driveratios and eight forward speed ratios. A sample of the numerical valuesfor the ratios is also provided in the truth table of FIG. 4 b. Thesevalues are determined utilizing the ring gear/sun gear tooth ratios alsogiven in FIG. 4 b. The N_(R1)/S_(R1) value is the tooth ratio for theplanetary gear set 320; the N_(R2)/S_(R2) value is the tooth ratio forthe planetary gear set 330; and the N_(R3)/S_(R3) value is the toothratio for the planetary gear set 340. Also given in FIG. 4 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reverse to first forward speed ratio. For example, the first tosecond forward speed ratio step is 2.28. It can be readily determinedfrom the truth table of FIG. 4 b that each of the forward single stepand double step ratio interchanges is a single transition shift.

A powertrain 410, shown in FIG. 5 a, includes the engine and torqueconverter 12, a planetary transmission 414 and the final drive mechanism16. The planetary transmission 414 includes a planetary gear arrangement418, input shaft 17 and output shaft 19. The planetary gear arrangement418 includes three simple planetary gear sets 420, 430 and 440.

The planetary gear set 420 includes a sun gear member 422, a ring gearmember 424, and a planet carrier assembly member 426. The planet carrierassembly member 426 includes a plurality of pinion gears 427 rotatablymounted on a carrier member 429 and disposed in meshing relationshipwith both the sun gear member 422 and the ring gear member 424.

The planetary gear set 430 includes a sun gear member 432, a ring gearmember 434, and a planet carrier assembly member 436. The planet carrierassembly member 436 includes a plurality of pinion gears 437 rotatablymounted on a carrier member 439 and disposed in meshing relationshipwith both the sun gear member 432 and the ring gear member 434.

The planetary gear set 440 includes a sun gear member 442, a ring gearmember 444, and a planet carrier assembly member 446. The planet carrierassembly member 446 includes a plurality of pinion gears 447 rotatablymounted on a carrier member 449 and disposed in meshing relationshipwith both the sun gear member 442 and the ring gear member 444.

The planetary gear arrangement 418 also includes seventorque-transmitting mechanisms 450, 452, 454, 456, 457, 458 and 459. Thetorque-transmitting mechanisms 450, 452, 454 and 456 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 457, 458 and 459 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the sun gear member422, and the output shaft 19 is continuously connected with the ringgear member 444. The planet carrier assembly member 426 is continuouslyconnected with the ring gear member 434 through the interconnectingmember 470. The planet carrier assembly member 436 is continuouslyconnected with the sun gear member 442 through the interconnectingmember 472. The sun gear member 432 is continuously connected with thetransmission housing 460 through the interconnecting member 474.

The planet carrier assembly member 426 is selectively connectable withthe sun gear member 422 through the clutch 450. The sun gear member 422is selectively connectable with the planet carrier assembly member 446through the clutch 452. The ring gear member 424 is selectivelyconnectable with the planet carrier assembly member 436 through theclutch 454. The planet carrier assembly member 446 is selectivelyconnectable with the ring gear member 444 through the clutch 456. Theplanet carrier assembly member 426 is selectively connectable with thetransmission housing 460 through the brake 457. The ring gear member 424is selectively connectable with the transmission housing 460 through thebrake 458. The planet carrier assembly member 446 is selectivelyconnectable with the transmission housing 460 through the brake 459.

The truth table shown in FIG. 5 b describes the engagement combinationand sequence of the torque-transmitting mechanisms 450, 452, 454, 456,457, 458 and 459 that are employed to provide three reverse drive ratiosand eight forward speed ratios.

Also given in the truth table of FIG. 5 b is a set of numerical valuesthat are attainable with the present invention utilizing the ringgear/sun gear tooth ratios shown. The N_(R1)/S_(R1) value is the toothratio of the planetary gear set 420; the N_(R2)/S_(R2) value is thetooth ratio of the planetary gear set 430; and the N_(R3)/S_(R3) valueis the tooth ratio of the planetary gear set 440. As can also bedetermined from the truth table of FIG. 5 b, all of the single step anddouble step forward interchanges are of the single transition variety.

FIG. 5 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse ratio and first forward ratio.For example, the ratio step between the first and second forward ratiosis 1.81.

A powertrain 510, shown in FIG. 6 a, includes an engine and torqueconverter 12, a planetary gear transmission 514 and the final drivemechanism 16. The planetary transmission 514 includes the input shaft17, a planetary gear arrangement 518 and the output shaft 19. Theplanetary gear arrangement 518 includes three planetary gear sets 520,530 and 540.

The planetary gear set 520 includes a sun gear member 522, a ring gearmember 524, and a planet carrier assembly member 526. The planet carrierassembly member 526 includes a plurality of pinion gears 527 rotatablymounted on a carrier member 529 and disposed in meshing relationshipwith both the sun gear member 522 and the ring gear member 524.

The planetary gear set 530 includes a sun gear member 532, a ring gearmember 534, and a planet carrier assembly member 536. The planet carrierassembly member 536 includes a plurality of pinion gears 537 rotatablymounted on a carrier member 539 and disposed in meshing relationshipwith both the sun gear member 532 and the ring gear member 534.

The planetary gear set 540 includes a sun gear member 542, a ring gearmember 544, and a planet carrier assembly member 546. The planet carrierassembly member 546 includes a plurality of pinion gears 547 rotatablymounted on a carrier member 549 and disposed in meshing relationshipwith both the sun gear member 542 and the ring gear member 544.

The planetary gear arrangement 518 also includes seventorque-transmitting mechanisms 550, 552, 554, 556, 557, 558 and 559. Thetorque-transmitting mechanisms 550, 552, 554, 556 and 557 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 558 and 559 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the sun gear member522, and the output shaft 19 is continuously connected with the planetcarrier assembly member 526. The ring gear member 524 is continuouslyconnected with the ring gear member 534 through the interconnectingmember 570. The interconnecting member 570 may be one component orseparate components. The planet carrier assembly member 536 iscontinuously connected with the ring gear member 544 through theinterconnecting member 572. The sun gear member 532 is continuouslyconnected with the transmission housing 560 through the interconnectingmember 574.

The ring gear member 524 is selectively connectable with the planetcarrier assembly member 546 through the clutch 550. The ring gear member534 is selectively connectable with the sun gear member 542 through theclutch 552. The sun gear member 522 is selectively connectable with theplanet carrier assembly member 546 through the clutch 554. The sun gearmember 522 is selectively connectable with the sun gear member 542through the clutch 556. The planet carrier assembly member 526 isselectively connectable with the sun gear member 542 through the clutch557. The ring gear member 524 is selectively connectable with thetransmission housing 560 through the brake 558. The planet carrierassembly member 546 is selectively connectable with the transmissionhousing through the brake 559.

The truth table shown in FIG. 6 b describes the engagement sequence andcombination of the torque-transmitting mechanisms to provide the reversespeed ratio and eight forward speed ratios. It should be noted that thetorque-transmitting mechanism 559 remains engaged through the neutralcondition, thereby simplifying the forward/reverse interchange. Thechart of FIG. 6 b describes the ratio steps between adjacent forwardspeed ratios and the ratio step between the reverse and first forwardspeed ratio.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6 b. TheN_(R1)/S_(R1) value is the tooth ratio of the planetary gear set 520;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set530; and the N_(R3)/S_(R3) value is the tooth ratio of the planetarygear set 540. As can also be determined from the truth table of FIG. 6b, each of the single step forward interchanges is of the singletransition variety.

A powertrain 610, shown in FIG. 7 a, has the engine and torque converter12, a planetary transmission 614 and the final drive mechanism 16. Theplanetary transmission 614 includes the input shaft 17, a planetary geararrangement 618 and the output shaft 19. The planetary gear arrangement618 includes three planetary gear sets 620, 630 and 640.

The planetary gear set 620 includes a sun gear member 622, a ring gearmember 624, and a planet carrier assembly member 626. The planet carrierassembly member 626 includes a plurality of pinion gears 627 rotatablymounted on a carrier member 629 and disposed in meshing relationshipwith both the sun gear member 622 and the ring gear member 624.

The planetary gear set 630 includes a sun gear member 632, a ring gearmember 634, and a planet carrier assembly member 636. The planet carrierassembly member 636 includes a plurality of pinion gears 637 rotatablymounted on a carrier member 639 and disposed in meshing relationshipwith both the sun gear member 632 and the ring gear member 634.

The planetary gear set 640 includes a sun gear member 642, a ring gearmember 644, and a planet carrier assembly member 646. The planet carrierassembly member 646 includes a plurality of pinion gears 647 rotatablymounted on a carrier member 649 and disposed in meshing relationshipwith both the sun gear member 642 and the ring gear member 644.

The planetary gear arrangement 618 also includes seventorque-transmitting mechanisms 650, 652, 654, 656, 657, 658 and 659. Thetorque-transmitting mechanisms 650, 652, 654, 656 and 657 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 658 and 659 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the sun gear member622, and the output shaft 19 is continuously connected with the ringgear member 644. The ring gear member 624 is continuously connected withthe planet carrier assembly member 636 through the interconnectingmember 670. The ring gear member 634 is continuously connected with thesun gear member 642 through the interconnecting member 672. The sun gearmember 632 is continuously connected with the transmission housing 660through the interconnecting member 674.

The planet carrier assembly member 626 is selectively connectable withthe sun gear member 622 through the clutch 650. The planet carrierassembly member 636 is selectively connectable with the ring gear member644 through the clutch 652. The planet carrier assembly member 626 isselectively connectable with the planet carrier assembly member 646through the clutch 654. The sun gear member 622 is selectivelyconnectable with the planet carrier assembly member 646 through theclutch 656. The ring gear member 644 is selectively connectable with theplanet carrier assembly member 646 through the clutch 657. The ring gearmember 624 is selectively connectable with the transmission housing 660through the brake 658. The planet carrier assembly member 626 isselectively connectable with the transmission housing 660 through thebrake 659.

The truth table shown in FIG. 7 b describes the combination oftorque-transmitting mechanism engagements that will provide the tworeverse drive ratios and eight forward speed ratios (as well as an extrafifth forward speed ratio (5′) and an extra seventh forward speed ratio(7′)), and the sequence of these engagements and interchanges.

The ratio values given are by way of example and are establishedutilizing the ring gear/sun gear tooth ratios given in FIG. 7 b. Forexample, the N_(R1)/S_(R1) value is the tooth ratio of the planetarygear set 620; the N_(R2)/S_(R2) value is the tooth ratio of theplanetary gear set 630; and the N_(R3)/S_(R3) value is the tooth ratioof the planetary gear set 640. The ratio steps between adjacent forwardratios and the second reverse to first ratio are also given in FIG. 7 b.For example, the ratio step between the first and second forward ratiois 2.14. As can also be determined from the truth table of FIG. 7 b,each of the single step forward interchanges are of the singletransition variety. Additionally, the torque-transmitting mechanism 559remains engaged through the neutral condition, thus simplifying theforward/reverse interchange.

A powertrain 710, shown in FIG. 8 a, has the conventional engine andtorque converter 12, a planetary transmission 714, and the conventionalfinal drive mechanism 16. The engine and torque converter 12 aredrivingly connected with the planetary transmission 714 through theinput shaft 17. The planetary transmission 714 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 714 includes a planetary gear arrangement 718that has a first planetary gear set 720, a second planetary gear set730, and a third planetary gear set 740.

The planetary gear set 720 includes a sun gear member 722, a ring gearmember 724, and a planet carrier assembly member 726. The planet carrierassembly member 726 includes a plurality of pinion gears 727 rotatablymounted on a carrier member 729 and disposed in meshing relationshipwith both the sun gear member 722 and the ring gear member 724.

The planetary gear set 730 includes a sun gear member 732, a ring gearmember 734, and a planet carrier assembly member 736. The planet carrierassembly member 736 includes a plurality of pinion gears 737 rotatablymounted on a carrier member 739 and disposed in meshing relationshipwith both the sun gear member 732 and the ring gear member 734.

The planetary gear set 740 includes a sun gear member 742, a ring gearmember 744, and a planet carrier assembly member 746. The planet carrierassembly member 746 includes a plurality of pinion gears 747 rotatablymounted on a carrier member 749 and disposed in meshing relationshipwith both the sun gear member 742 and the ring gear member 744.

The planetary gear arrangement 718 also includes seventorque-transmitting mechanisms 750, 752, 754, 756, 757, 758 and 759. Thetorque-transmitting mechanisms 750, 752, 754, 756 and 757 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 758 and 759 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 746, and the output shaft 19 is continuously connectedwith the planet carrier assembly member 736. The sun gear member 722 iscontinuously connected with the planet carrier assembly member 736through the interconnecting member 770. The ring gear member 734 iscontinuously connected with the sun gear member 742 through theinterconnecting member 772. The sun gear member 732 is continuouslyconnected with the transmission housing 760 through the interconnectingmember 774.

The planet carrier assembly member 736 is selectively connectable withthe planet carrier assembly member 746 through the clutch 750. Theplanet carrier assembly member 726 is selectively connectable with thering gear member 734 through the clutch 752. The planet carrier assemblymember 726 is selectively connectable with the ring gear member 744through the clutch 754. The ring gear member 724 is selectivelyconnectable with the planet carrier assembly member 746 through theclutch 756. The ring gear member 724 is selectively connectable with thering gear member 744 through the clutch 757. The planet carrier assemblymember 726 is selectively connectable with the transmission housing 760through the brake 758. The ring gear member 724 is selectivelyconnectable with the transmission housing 760 through the brake 759.

The truth table of FIG. 8 b defines the torque-transmitting mechanismengagement sequence utilized for each of the nine forward speed ratiosand the reverse speed ratio. Also given in the truth table is a set ofnumerical values that are attainable with the present inventionutilizing the ring gear/sun gear tooth ratios given in FIG. 8 b. TheN_(R1)/S_(R1), value is the tooth ratio of the planetary gear set 720;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set730; and the N_(R3/S) _(R3) value is the tooth ratio of the planetarygear set 740. As may be determined from the truth table of FIG. 8 b,each of the single step forward interchanges is of the single transitionvariety. Additionally, the torque-transmitting mechanism 758 remainsengaged through the neutral condition, thus simplifying theforward/reverse interchange.

FIG. 8 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is2.39.

A powertrain 810, shown in FIG. 9 a, has the conventional engine andtorque converter 12, a planetary transmission 814, and the final drivemechanism 16. The engine and torque converter 12 are drivingly connectedwith the planetary transmission 814 through the input shaft 17. Theplanetary transmission 814 is drivingly connected with the final drivemechanism 16 through the output shaft 19. The planetary transmission 814includes a planetary gear arrangement 818 that has a first planetarygear set 820, a second planetary gear set 830, and a third planetarygear set 840.

The planetary gear set 820 includes a sun gear member 822, a ring gearmember 824, and a planet carrier assembly member 826. The planet carrierassembly member 826 includes a plurality of pinion gears 827 rotatablymounted on a carrier member 829 and disposed in meshing relationshipwith both the sun gear member 822 and the ring gear member 824.

The planetary gear set 830 includes a sun gear member 832, a ring gearmember 834, and a planet carrier assembly member 836. The planet carrierassembly member 836 includes a plurality of pinion gears 837 rotatablymounted on a carrier member 839 and disposed in meshing relationshipwith both the sun gear member 832 and the ring gear member 834.

The planetary gear set 840 includes a sun gear member 842, a ring gearmember 844, and a planet carrier assembly member 846. The planet carrierassembly member 846 includes a plurality of pinion gears 847 rotatablymounted on a carrier member 849 and disposed in meshing relationshipwith both the sun gear member 842 and the ring gear member 844.

The planetary gear arrangement 818 also includes seventorque-transmitting mechanisms 850, 852, 854, 856, 857, 858 and 859. Thetorque-transmitting mechanisms 850, 852, 854 and 856 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 857, 858 and 859 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the sun gear member842, and the output shaft 19 is continuously connected with the sun gearmember 822. The ring gear member 824 is continuously connected with theplanet carrier assembly member 836 through the interconnecting member870. The ring gear member 834 is continuously connected with the planetcarrier assembly member 846 through the interconnecting member 872. Thesun gear member 832 is continuously connected with the transmissionhousing 860 through the interconnecting member 874.

The planet carrier assembly member 826 is selectively connectable withthe planet carrier assembly member 836 through the clutch 850. Theplanet carrier assembly member 836 is selectively connectable with thering gear member 844 through the clutch 852. The planet carrier assemblymember 826 is selectively connectable with the sun gear member 842through the clutch 854. The sun gear member 842 is selectivelyconnectable with the planet carrier assembly member 846 through theclutch 856. The planet carrier assembly member 846 is selectivelyconnectable with the transmission housing 860 through the brake 857. Theplanet carrier assembly member 826 is selectively connectable with thetransmission housing 860 through the brake 858. The ring gear member 844is selectively connectable with the transmission housing 860 through thebrake 859.

The truth table shown in FIG. 9 b defines the torque-transmittingmechanism engagement sequence that provides the three reverse speedratios and eight forward speed ratios shown in the truth table andavailable with the planetary gear arrangement 818. A sample of numericalvalues for the individual ratios is also given in the truth table ofFIG. 9 b. These numerical values have been calculated using the ringgear/sun gear tooth ratios also given by way of example in FIG. 9 b. TheN_(R1)/S_(R1) value is the tooth ratio of the planetary gear set 820;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set830; and the N_(R3)/S_(R3) value is the tooth ratio of the planetarygear set 840. It can be readily recognized from the truth table that allof the single step and double step forward interchanges are of thesingle transition variety. FIG. 9 b also describes the ratio stepsbetween adjacent forward ratios and between the third reverse (Reverse3) and first forward ratio. For example, the ratio step between thefirst and second forward ratios is 1.91.

The powertrain 910, shown in FIG. 10 a, includes the conventional engineand torque converter 12, a planetary transmission 914, and theconventional final drive mechanism 16. The engine and torque converter12 are drivingly connected with the planetary transmission 914 throughthe input shaft 17. The planetary transmission 914 is drivinglyconnected with the final drive mechanism 16 through the output shaft 19.The planetary transmission 914 includes a planetary gear arrangement 918that has a first planetary gear set 920, a second planetary gear set930, and a third planetary gear set 940.

The planetary gear set 920 includes a sun gear member 922, a ring gearmember 924, and a planet carrier assembly member 926. The planet carrierassembly 926 includes a plurality of pinion gears 927 that are rotatablymounted on a carrier member 929 and disposed in meshing relationshipwith both the sun gear member 922 and the ring gear member 924.

The planetary gear set 930 includes a sun gear member 932, a ring gearmember 934, and a planet carrier assembly member 936. The planet carrierassembly member 936 includes a plurality of pinion gears 937 rotatablymounted on a carrier member 939 and disposed in meshing relationshipwith both the sun gear member 932 and the ring gear member 934.

The planetary gear set 940 includes a sun gear member 942, a ring gearmember 944, and a planet carrier assembly member 946. The planet carrierassembly member 946 includes a plurality of pinion gears 947 rotatablymounted on a carrier member 949 and disposed in meshing relationshipwith both the sun gear member 942 and the ring gear member 944.

The planetary gear arrangement 918 also includes seventorque-transmitting mechanisms 950, 952, 954, 956, 957, 958 and 959. Thetorque-transmitting mechanisms 950, 952, 954, 956 and 957 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 958 and 959 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is continuously connected with the sun gear member922, and the output shaft 19 is continuously connected with the planetcarrier assembly member 946. The ring gear member 924 is continuouslyconnected with the ring gear member 934 through the interconnectingmember 970. The interconnecting member 970 may be one component orseparate components. The sun gear member 932 is continuously connectedwith the sun gear member 942 through the interconnecting member 972. Theinterconnecting member 972 may be one component or separate components.The planet carrier assembly member 936 is continuously connected withthe transmission housing 960 through the interconnecting member 974.

The ring gear member 934 is selectively connectable with the planetcarrier assembly member 946 through the clutch 950. The sun gear member922 is selectively connectable with the ring gear member 944 through theclutch 952. The planet carrier assembly member 926 is selectivelyconnectable with the planet carrier assembly member 946 through theclutch 954. The planet carrier assembly member 926 is selectivelyconnectable with the ring gear member 944 through the clutch 956. Thesun gear member 932 is selectively connectable with the planet carrierassembly member 946 through the clutch 957. The ring gear member 924 isselectively connectable with the transmission housing 960 through thebrake 958. The planet carrier assembly member 926 is selectivelyconnectable with the transmission housing 960 through the brake 959.

The truth table of FIG. 10 b describes the torque-transmitting mechanismengagement sequence utilized to provide two reverse speed ratios andnine forward speed ratios (as well as an extra fourth forward speedratio (4′)). The truth table also provides a set of examples for theratios for each of the reverse and forward speed ratios. These numericalvalues have been determined utilizing the ring gear/sun gear toothratios given in FIG. 10 b. The N_(R1)/S_(R1) value is the tooth ratio ofthe planetary gear set 920; the N_(R2)/S_(R2) value is the tooth ratioof the planetary gear set 930; and the N_(R3)/S_(R3) value is the toothratio of the planetary gear set 940. As can also be determined from thetruth table of FIG. 10 b, each of the single step and double stepforward interchanges are of the single transition variety.

A powertrain 1010, shown in FIG. 11 a, includes the conventional engineand torque converter 12, a planetary transmission 1014, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1014 through theinput shaft 17. The planetary transmission 1014 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1014 includes a planetary gear arrangement 1018that has a first planetary gear set 1020, a second planetary gear set1030, and a third planetary gear set 1040.

The planetary gear set 1020 includes a sun gear member 1022, a ring gearmember 1024, and a planet carrier assembly member 1026. The planetcarrier assembly member 1026 includes a plurality of pinion gears 1027rotatably mounted on a carrier member 1029 and disposed in meshingrelationship with both the sun gear member 1022 and the ring gear member1024.

The planetary gear set 1030 includes a sun gear member 1032, a ring gearmember 1034, and a planet carrier assembly member 1036. The planetcarrier assembly member 1036 includes a plurality of pinion gears 1037rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with both the sun gear member 1032 and the ring gear member1034.

The planetary gear set 1040 includes a sun gear member 1042, a ring gearmember 1044, and a planet carrier assembly member 1046. The planetcarrier assembly member 1046 includes a plurality of pinion gears 1047rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with both the sun gear member 1042 and the ring gear member1044.

The planetary gear arrangement 1018 also includes seventorque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057, 1058 and1059. The torque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057,1058 and 1059 are rotating type torque-transmitting mechanisms, commonlytermed clutches.

The input shaft 17 is continuously connected with the sun gear member1022, and the output shaft 19 is continuously connected with the ringgear member 1044. The planet carrier assembly member 1026 iscontinuously connected with the ring gear member 1034 through theinterconnecting member 1070. The planet carrier assembly member 1036 iscontinuously connected with the planet carrier assembly member 1046through the interconnecting member 1072. The sun gear member 1032 iscontinuously connected with the transmission housing 1060 through theinterconnecting member 1074.

The sun gear member 1032 is selectively connectable with the planetcarrier assembly member 1046 through the clutch 1050. The planet carrierassembly member 1026 is selectively connectable with the sun gear member1022 through the clutch 1052. The planet carrier assembly member 1026 isselectively connectable with the ring gear member 1044 through theclutch 1054. The sun gear member 1022 is selectively connectable withthe planet carrier assembly member 1036 through the clutch 1056. The sungear member 1022 is selectively connectable with the ring gear member1044 through the clutch 1057. The ring gear member 1024 is selectivelyconnectable with the ring gear member 1044 through the clutch 1058. Thering gear member 1024 is selectively connectable with the sun gearmember 1042 through the clutch 1059.

The truth table shown in FIG. 11 b describes the engagement combinationsand the engagement sequence necessary to provide a reverse drive ratioand eight forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 11 b. These valuesare determined utilizing the ring gear/sun gear tooth ratios also givenin FIG. 11 b. The N_(R1)/S_(R1) value is the tooth ratio for theplanetary gear set 1020; the N_(R2)/S_(R2) value is the tooth ratio forthe planetary gear set 1030; and the N_(R3)/S_(R3) value is the toothratio for the planetary gear set 1040. As can be determined from FIG. 11b, each of the single step forward interchanges is of the singletransition variety. Additionally, the torque-transmitting mechanism 1050remains engaged through the neutral condition, thus simplifying theforward/reverse interchange. Also given in FIG. 11 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reverse to first forward speed ratio.

A powertrain 1110, shown in FIG. 12 a, includes the conventional engineand torque converter 12, a planetary transmission 1114, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1114 through theinput shaft 17. The planetary transmission 1114 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1114 includes a planetary gear arrangement 1118that has a first planetary gear set 1120, a second planetary gear set1130, and a third planetary gear set 1140.

The planetary gear set 1120 includes a sun gear member 1122, a ring gearmember 1124, and a planet carrier assembly member 1126. The planetcarrier assembly member 1126 includes a plurality of pinion gears 1127rotatably mounted on a carrier member 1129 and disposed in meshingrelationship with both the sun gear member 1122 and the ring gear member1124.

The planetary gear set 1130 includes a sun gear member 1132, a ring gearmember 1134, and a planet carrier assembly member 1136. The planetcarrier assembly member 1136 includes a plurality of pinion gears 1137rotatably mounted on a carrier member 1139 and disposed in meshingrelationship with both the sun gear member 1132 and the ring gear member1134.

The planetary gear set 1140 includes a sun gear member 142, a ring gearmember 1144, and a planet carrier assembly member 1146. The planetcarrier assembly member 1146 includes a plurality of pinion gears 1147rotatably mounted on a carrier member 1149 and disposed in meshingrelationship with both the sun gear member 1142 and the ring gear member1144.

The planetary gear arrangement 1118 also includes seventorque-transmitting mechanisms 1150, 1152, 1154, 1156, 1157, 1158 and1159. The torque-transmitting mechanism 1150 is a stationary typetorque-transmitting mechanism, commonly termed a brake or reactionclutch. The torque-transmitting mechanisms 1152, 1154, 1156, 1157, 1158and 1159 are rotating type torque-transmitting mechanisms, commonlytermed clutches.

The input shaft 17 is continuously connected with the ring gear member1144, and the output shaft 19 is continuously connected with the planetcarrier assembly member 1126. The ring gear member 1124 is continuouslyconnected with the planet carrier assembly member 1136 through theinterconnecting member 1170. The sun gear member 1132 is continuouslyconnected with the planet carrier assembly member 1146 through theinterconnecting member 1172. The ring gear member 11334 is continuouslyconnected with the transmission housing 1160 through the interconnectingmember 1174.

The ring gear member 1124 is selectively connectable with thetransmission housing 1160 through the brake 1150. The planet carrierassembly member 1136 is selectively connectable with the ring gearmember 1144 through the clutch 1152. The sun gear member 1122 isselectively connectable with the sun gear member 1132 through the clutch1154. The sun gear member 1122 is selectively connectable with the ringgear member 1144 through the clutch 1156. The sun gear member 1122 isselectively connectable with the sun gear member 1142 through the clutch1157. The planet carrier assembly member 1126 is selectively connectablewith the sun gear member 1132 through the clutch 1158. The planetcarrier assembly member 1126 is selectively connectable with the ringgear member 1144 through the clutch 1159.

The truth table shown in FIG. 12 b describes the engagement combinationsand the engagement sequence necessary to provide a reverse drive ratioand eight forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 12 b. The values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 12 b. The N_(R1)/S_(R1) value is the tooth ratio of the planetarygear set 1120; the N_(R2)/S_(R2) value is the tooth ratio of theplanetary gear set 1130; and the N_(R3)/S_(R3) value is the tooth ratioof the planetary gear set 1140. As can also be determined from the truthtable of FIG. 12 b, the torque-transmitting mechanism 1150 remainsengaged through the neutral condition, thus simplifying theforward/reverse interchange. Also given in FIG. 12 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reversed first forward speed ratio. For example, step ratio betweenthe first and second forward speed ratios is 1.40.

A powertrain 1210, shown in FIG. 13 a, includes the conventional engineand torque converter 12, a planetary transmission 1214, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1214 through theinput shaft 17. The planetary transmission 1214 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1214 includes a planetary gear arrangement 1218that has a first planetary gear set 1220, a second planetary gear set1230, and a third planetary gear set 1240.

The planetary gear set 1220 includes a sun gear member 1222, a ring gearmember 1224, and a planet carrier assembly member 1226. The planetcarrier assembly member 1226 includes a plurality of pinion gears 1227rotatably mounted on a carrier member 1229 and disposed in meshingrelationship with both the sun gear member 1222 and the ring gear member1224.

The planetary gear set 1230 includes a sun gear member 1232, a ring gearmember 1234, and a planet carrier assembly member 1236. The planetcarrier assembly member 1236 includes a plurality of pinion gears 1237rotatably mounted on a carrier member 1239 and disposed in meshingrelationship with both the sun gear member 1232 and the ring gear member1234.

The planetary gear set 1240 includes a sun gear member 1242, a ring gearmember 1244, and a planet carrier assembly member 1246. The planetcarrier assembly member 1246 includes a plurality of pinion gears 1247rotatably mounted on a carrier member 1249 and disposed in meshingrelationship with both the sun gear member 1242 and the ring gear member1244.

The planetary gear arrangement 1218 also includes seventorque-transmitting mechanisms 1250, 1252, 1254, 1256, 1257, 1258 and1259. The torque-transmitting mechanisms 1250, 1252, 1254, 1256, 1257,and 1258 are rotating type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1259 is a stationarytype torque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is continuously connected with the planet carrierassembly member 1246, and the output shaft 19 is continuously connectedwith the ring gear member 1224. The sun gear member 1222 is continuouslyconnected with the sun gear member 1232 through the interconnectingmember 1270. The interconnecting member 1270 may be one component orseparate components. The planet carrier assembly member 1236 iscontinuously connected with the sun gear member 1242 through theinterconnecting member 1272. The ring gear member 1234 is continuouslyconnected with the transmission housing 1260 through the interconnectingmember 1274.

The ring gear member 1224 is selectively connectable with the sun gearmember 1232 through the clutch 1250. The sun gear member 1232 isselectively connectable with the planet carrier assembly member 1246through the clutch 1252. The ring gear member 1232 is selectivelyconnectable with the planet carrier assembly member 1246 through theclutch 1254. The ring gear member 1224 is selectively connectable withthe planet carrier assembly member 12236 through the clutch 1256. Theplanet carrier assembly member 1226 is selectively connectable with theplanet carrier assembly member 1246 through the clutch 1257. The planetcarrier assembly member 1226 is selectively connectable with the ringgear member 1244 through the clutch 1258. The planet carrier assemblymember 1236 is selectively connectable with the transmission housing1260 through the brake 1259.

The truth table shown in FIG. 13 b described the engagement combinationsand the engagement sequence necessary to provide a reverse drive ratioand eight forward speed ratios (as well as an extra third forward speedratio (3′) and an extra sixth forward speed ratio (6′)). A sample of thenumerical values for the ratios is also provided in the truth table ofFIG. 13 b. These values are determined utilizing the ring gear/sun geartooth ratios also given in FIG. 13 b. The N_(R1)/S_(R1) value is thetooth ratio of the planetary gear set 1220; the N_(R2)/S_(R2) value isthe tooth ratio of the planetary gear set 1230; and the N_(R3)/S_(R3)value is the tooth ratio of the planetary gear set 1240. As can bedetermined from the truth table of FIG. 13 b, each of the single stepforward interchanges is of the single transition variety. Also given inFIG. 13 b is a chart describing the step ratios between the adjacentforward speed ratios and the reverse to first forward speed ratio.

A powertrain 1310, shown in FIG. 11 a, includes the conventional engineand torque converter 12, a planetary transmission 1314, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1014 through theinput shaft 17. The planetary transmission 1314 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1314 includes a planetary gear arrangement 1318that has a first planetary gear set 1320, a second planetary gear set1330, and a third planetary gear set 1340.

The planetary gear set 1320 includes a sun gear member 1322, a ring gearmember 1324, and a planet carrier assembly member 1326. The planetcarrier assembly member 1326 includes a plurality of pinion gears 1327rotatably mounted on a carrier member 1329 and disposed in meshingrelationship with both the sun gear member 1322 and the ring gear member1324.

The planetary gear set 1330 includes a sun gear member 1332, a ring gearmember 1334, and a planet carrier assembly member 1336. The planetcarrier assembly member 1336 includes a plurality of pinion gears 1337rotatably mounted on a carrier member 1339 and disposed in meshingrelationship with both the sun gear member 1332 and the ring gear member1334.

The planetary gear set 1340 includes a sun gear member 1342, a ring gearmember 1344, and a planet carrier assembly member 1346. The planetcarrier assembly member 1346 includes a plurality of pinion gears 1347rotatably mounted on a carrier member 1349 and disposed in meshingrelationship with both the sun gear member 1342 and the ring gear member1344.

The planetary gear arrangement 1318 also includes seventorque-transmitting mechanisms 1350, 1352, 1354, 1356, 1357, 1358 and1359. The torque-transmitting mechanisms 1350, 1352, 1354, 1356, 1357and 1358 are rotating type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1359 is a stationarytype torque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is continuously connected with the sun gear member1322, and the output shaft 19 is continuously connected with the planetcarrier assembly member 1326. The ring gear member 1324 is continuouslyconnected with the sun gear member 1332 through the interconnectingmember 1370. The planet carrier assembly member 1336 is continuouslyconnected with the ring gear member 1334 through the interconnectingmember 1372. The ring gear member 1334 is continuously connected withthe transmission housing 1360 through the interconnecting member 1374.

The sun gear member 1332 is selectively connectable with the planetcarrier assembly member 1346 through the clutch 1350. The ring gearmember 1324 is selectively connectable with the sun gear member 1342through the clutch 1352. The sun gear member 1322 is selectivelyconnectable with the planet carrier assembly member 1346 through theclutch 1354. The sun gear member 1322 is selectively connectable withthe sun gear member 1342 through the clutch 1356. The planet carrierassembly member 1326 is selectively connectable with the planet carrierassembly member 1336 through the clutch 1357. The planet carrierassembly member 1326 is selectively connectable with the sun gear member1342 through the clutch 1358. The planet carrier assembly member 1346 isselectively connectable with the transmission housing 1360 through thebrake 1359.

The truth table shown in FIG. 14 b describes the engagement combinationsand the engagement sequence necessary to provide two reverse driveratios and eight forward speed ratios. As sample of the numerical valuesfor the ratios is also provided in the truth table of FIG. 14 b. Thesevalues are determined utilizing the ring gear/sun gear tooth ratios alsogiven in FIG. 14 b. The N_(R1)/S_(R1) value is the tooth ratio of theplanetary gear set 1320; the N_(R2)/S_(R2) value is the tooth ratio ofthe planetary gear set 1330; and the N_(R3)/S_(R3) value is the toothratio of the planetary gear set 1340. As can also be determined from thetruth table of FIG. 14 b, each of the single step forward interchangesis of the single transition variety. Additionally, thetorque-transmitting mechanism 1359 remains engaged through the neutralcondition, thus simplifying the forward/reverse interchange. Also givenin FIG. 14 b is a chart describing the step ratios between the adjacentforward speed ratios and the second reverse (Reverse 2) to first forwardspeed ratio.

A powertrain 1410, shown in FIG. 15 a, includes the conventional engineand torque converter 12, a planetary transmission 1414, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1414 through theinput shaft 17. The planetary transmission 1414 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1414 includes a planetary gear arrangement 1418that has a first planetary gear set 1420, a second planetary gear set1430, and a third planetary gear set 1440.

The planetary gear set 1420 includes a sun gear member 1422, a ring gearmember 1424, and a planet carrier assembly member 1426. The planetcarrier assembly member 1426 includes a plurality of pinion gears 1427rotatably mounted on a carrier member 1429 and disposed in meshingrelationship with both the sun gear member 1422 and the ring gear member1424.

The planetary gear set 1430 includes a sun gear member 1432, a ring gearmember 1434, and a planet carrier assembly member 1436. The planetcarrier assembly member 1436 includes a plurality of pinion gears 1437rotatably mounted on a carrier member 1439 and disposed in meshingrelationship with both the sun gear member 1432 and the ring gear member1434.

The planetary gear set 1440 includes a sun gear member 1442, a ring gearmember 1444, and a planet carrier assembly member 1446. The planetcarrier assembly member 1446 includes a plurality of pinion gears 1447rotatably mounted on a carrier member 1449 and disposed in meshingrelationship with both the sun gear member 1442 and the ring gear member1444.

The planetary gear arrangement 1418 also includes seventorque-transmitting mechanisms 1450, 1452, 1454, 1456, 1457, 1458 and1459. The torque-transmitting mechanisms 1450, 1452, 1454, 1456, 1457,1458 and 1459 are rotating type torque-transmitting mechanisms, commonlytermed clutches.

The input shaft 17 is continuously connected with the sun gear member1422, and the output shaft 19 is continuously connected with the planetcarrier assembly member 1446. The ring gear member 1424 is continuouslyconnected with the ring gear member 1434 through the interconnectingmember 1470. The planet carrier assembly member 1436 is continuouslyconnected with the ring gear member 1444 through the interconnectingmember 1472. The sun gear member 1432 is continuously connected with thetransmission housing 1460 through the interconnecting member 1474.

The sun gear member 1432 is selectively connectable with the planetcarrier assembly member 1436 through the clutch 1450. The ring gearmember 1434 is selectively connectable with the planet carrier assemblymember 1446 through the clutch 1452. The planet carrier assembly member1426 is selectively connectable with the planet carrier assembly member1436 through the clutch 1454. The planet carrier assembly member 1426 isselectively connectable with the sun gear member 1442 through the clutch1456. The planet carrier assembly member 1426 is selectively connectablewith the planet carrier assembly member 1446 through the clutch 1457.The sun gear member 1422 is selectively connectable with the planetcarrier assembly member 1436 through the clutch 1458. The sun gearmember 1422 is selectively connectable with the sun gear member 1442through the clutch 1459.

The truth table shown in FIG. 15 b describes the engagement combinationsand the engagement sequence necessary to provide three reverse driveratios and nine forward speed ratios (as well as an extra first forwardspeed ratio (1′) and another extra first forward speed ratio (1″)). Asample of the numerical values for the ratios is also provided in thetruth table of FIG. 15 b. These values are determined utilizing the ringgear/sun gear tooth ratios also given in FIG. 15 b. The N_(R1)/S_(R1)value is the tooth ratio of the planetary gear set 1420; theN_(R2)/S_(R2) value is the tooth ratio of the planetary gear set 1430;and the N_(R3)/S_(R3) value is the tooth ratio of the planetary gear set1440. As can also be determined from the truth table of FIG. 15 b, eachof the single step and double step forward interchanges is of the singletransition variety. Also given in FIG. 15 b is a chart describing thestep ratios between the adjacent forward speed ratios and the thirdreverse (Reverse 3) to first forward speed ratio.

A powertrain 1510, shown in FIG. 16 a, includes the conventional engineand torque converter 12, a planetary transmission 1514, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1514 through theinput shaft 17. The planetary transmission 1514 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1514 includes a planetary gear arrangement 1518that has a first planetary gear set 1520, a second planetary gear set1530, and a third planetary gear set 1540.

The planetary gear set 1520 includes a sun gear member 1522, a ring gearmember 1524, and a planet carrier assembly member 1526. The planetcarrier assembly member 1526 includes a plurality of pinion gears 1527rotatably mounted on a carrier member 1529 and disposed in meshingrelationship with both the sun gear member 1522 and the ring gear member1524.

The planetary gear set 1530 includes a sun gear member 1532, a ring gearmember 1534, and a planet carrier assembly member 1536. The planetcarrier assembly member 1536 includes a plurality of pinion gears 1537rotatably mounted on a carrier member 1539 and disposed in meshingrelationship with the sun gear member 1532. Pinion gears 1538 aredisposed in meshing relationship with both the ring gear member 1544 andthe pinion gears 1537.

The planetary gear set 1540 includes a sun gear member 1542, a ring gearmember 1544, and a planet carrier assembly member 1546. The planetcarrier assembly member 1546 includes a plurality of pinion gears 1547rotatably mounted on a carrier member 1549 and disposed in meshingrelationship with both the sun gear member 1542 and the ring gear member1544.

The planetary gear arrangement 1518 also includes seventorque-transmitting mechanisms 1550, 1552, 1554, 1556, 1557, 1558 and1559. The torque-transmitting mechanisms 1550, 1552, 1554, 1556 and 1557are rotating type torque-transmitting mechanisms, commonly termedclutches. The torque-transmitting mechanisms 1558 and 1559 arestationary type torque-transmitting mechanisms, commonly termed brakesor reaction clutches.

The input shaft 17 is continuously connected with the sun gear member1532, and the output shaft is continuously connected with the planetcarrier assembly member 1526. The sun gear member 1522 is continuouslyconnected with the sun gear member 1532 through the interconnectingmember 1570. The interconnecting member 1570 may be one component orseparate components. The ring gear member 1534 is continuously connectedwith the sun gear member 1542 through the interconnecting member 1572.The planet carrier assembly member 1536 is continuously connected withthe transmission housing 1560 through the interconnecting member 1574.

The sun gear member 1532 is selectively connectable with the planetcarrier assembly member 1546 through the clutch 1550. The ring gearmember 1524 is selectively connectable with the planet carrier assemblymember 1546 through the clutch 1552. The ring gear member 1524 isselectively connectable with the ring gear member 1544 through theclutch 1554. The planet carrier assembly member 1526 is selectivelyconnectable with the planet carrier assembly member 1546 through theclutch 1556. The planet carrier assembly member 1526 is selectivelyconnectable with the ring gear member 1544 through the clutch 1557. Theplanet carrier assembly member 1546 is selectively connectable with thetransmission housing 1560 through the brake 1558. The ring gear member1544 is selectively connectable with the transmission housing 1560through the brake 1559

The truth table shown in FIG. 16 b describes the engagement combinationsand the engagement sequence necessary to provide two reverse speedratios and eight forward speed ratios (as well as an extra first forwardspeed ratio (1′) and an extra third forward speed ratio (3′)). A sampleof the numerical values for the ratios is also provided in the truthtable of FIG. 16 b. These values are determined utilizing the ringgear/sun gear tooth ratios also given in FIG. 16 b. The N_(R1)/S_(R1)value is the tooth ratio of the planetary gear set 1520; theN_(R2)/S_(R2) value is the tooth ratio of the planetary gear set 1530;and the N_(R3)/S_(R3) value is the tooth ratio of the planetary gear set1540. As can also be determined from the truth table of FIG. 16 b, eachof the single step forward interchanges is of the single transitionvariety. Also given in FIG. 16 b is a chart describing the step ratiosbetween adjacent forward speed ratios and the second reverse (Reverse 2)to first forward speed ratio.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input shaft; an outputshaft; first, second and third planetary gear sets each having first,second and third members; said input shaft being continuouslyinterconnected with a member of said planetary gear sets, and saidoutput shaft being continuously interconnected with another member ofsaid planetary gear sets; a first interconnecting member continuouslyinterconnecting said first member of said first planetary gear set withsaid first member of said second planetary gear set; a secondinterconnecting member continuously interconnecting said second memberof said second planetary gear set with said first member of said thirdplanetary gear set; a third interconnecting member continuouslyinterconnecting said third member of said second planetary gear set witha stationary member, said third member of said second planetary gear setbeing different from said members interconnected with said input shaftand said output shaft, respectively; a first torque-transmittingmechanism selectively interconnecting a member of said first planetarygear set with a member of said second or third planetary gear set; asecond torque-transmitting mechanism selectively interconnecting amember of said third planetary gear set with a member of said first orsecond planetary gear set; a third torque-transmitting mechanismselectively interconnecting a member of said first planetary gear setwith another member of said first, second or third planetary gear set; afourth torque-transmitting mechanism selectively interconnecting amember of said third planetary gear set with another member of saidfirst, second or third planetary gear set; a fifth torque-transmittingmechanism selectively interconnecting a member of said first or thirdplanetary gear set with a member of said second planetary gear set, orwith said stationary member; a sixth torque-transmitting mechanismselectively interconnecting a member of said second or third planetarygear set with another member of said first, second or third planetarygear set, or with said stationary member; and a seventhtorque-transmitting mechanism selectively interconnecting a member ofsaid first, second or third planetary gear set with another member ofsaid first, second or third planetary gear set, or with said stationarymember; said torque-transmitting mechanisms being engaged incombinations of two to establish at least eight forward speed ratios andat least one reverse speed ratio between said input shaft and saidoutput shaft.
 2. The transmission defined in claim 1, wherein saidfirst, second, third and fourth torque-transmitting mechanisms compriseclutches, and said fifth, sixth and seventh torque-transmittingmechanisms comprise brakes.
 3. The transmission defined in claim 1,wherein said first, second, third, fourth and fifth torque-transmittingmechanisms comprise clutches, and said sixth and seventhtorque-transmitting mechanisms comprise brakes.
 4. The transmissiondefined in claim 1, wherein said first, second, third, fourth, fifth andsixth torque-transmitting mechanism comprise clutches and said seventhtorque-transmitting mechanism comprises a brake.
 5. The transmissiondefined in claim 1, wherein said first, second, third, fourth, fifth,sixth and seventh torque-transmitting mechanisms comprise clutches. 6.The transmission defined in claim 1, wherein planet carrier assemblymembers of each of said planetary gear sets are single-pinion carriers.7. The transmission defined in claim 1, wherein at least one planetcarrier assembly member of said planetary gear sets is a double-pinioncarrier.
 8. A multi-speed transmission comprising: an input shaft; anoutput shaft; a planetary gear arrangement having first, second andthird planetary gear sets, each planetary gear set having first, secondand third members; said input shaft being continuously interconnectedwith a member of said planetary gear sets, and said output shaft beingcontinuously interconnected with another member of said planetary gearsets; a first interconnecting member continuously interconnecting saidfirst member of said first planetary gear set with said first member ofsaid second planetary gear set; a second interconnecting membercontinuously interconnecting said second member of said second planetarygear set with said first member of said third planetary gear set; athird interconnecting member continuously interconnecting said thirdmember of said second planetary gear set with a stationary member, saidthird member of said second planetary gear set being different from saidmembers interconnected with said input shaft and said output shaft,respectively; and seven torque-transmitting mechanisms for selectivelyinterconnecting said members of said planetary gear sets with astationary member or with other members of said planetary gear sets,said seven torque-transmitting mechanisms being engaged in combinationsof two to establish at least eight forward speed ratios and at least onereverse speed ratio between said input shaft and said output shaft. 9.The transmission defined in claim 8, wherein a first of said seventorque-transmitting mechanisms is operable for selectivelyinterconnecting a member of said first planetary gear set with a memberof said second or third planetary gear set.
 10. The transmission definedin claim 8, wherein a second of said seven torque-transmittingmechanisms is operable for selectively interconnecting a member of saidthird planetary gear set with a member of said first or second planetarygear set.
 11. The transmission defined in claim 8, wherein a third ofsaid seven torque-transmitting mechanisms is operable for selectivelyinterconnecting a member of said first planetary gear set with anothermember of said first, second or third planetary gear set.
 12. Thetransmission defined in claim 8, wherein a fourth of said seventorque-transmitting mechanisms is operable for selectivelyinterconnecting a member of said third planetary gear set with anothermember of said first, second or third planetary gear set.
 13. Thetransmission defined in claim 8, wherein a fifth of said seventorque-transmitting mechanisms is operable for selectivelyinterconnecting a member of said first or third planetary gear set witha member of said second planetary gear set, or with said stationarymember.
 14. The transmission defined in claim 8, wherein a sixth of saidseven torque-transmitting mechanisms is operable for selectivelyinterconnecting a member of said second or third planetary gear set withanother member of said first, second or third planetary gear set, orwith said stationary member.
 15. The transmission defined in claim 8,wherein a seventh of said seven torque-transmitting mechanisms isoperable for selectively interconnecting a member of said first, secondor third planetary gear set with another member of said first, second orthird planetary gear set, or with said stationary member.
 16. Thetransmission defined in claim 8, wherein planet carrier assembly membersof each of said planetary gear sets are single-pinion carriers.
 17. Thetransmission defined in claim 8, wherein at least one planet carrierassembly member of said planetary gear sets is a double-pinion carrier.